Taylor Made v. AtlificInc., 2012 ONCA 459 is a helpful source for the well-established principle that:
In circumstances of joint and several liability under a contract, judgment against one party does not bar further action against another for the same cause of action. Campbell Flour Co. Ltd. v. Bowes (1914), 32 O.L.R. 270 (C.A.) at pp. 279-80; Courts of Justice Act, R.S.O. 1990, c. C-43, s. 139(1).